Kinetic energy absorbing device



Jan. 14, 1964 W. G. PRICE ETAL KINETIC ENERGY ABSORBING DEVICE 2 Sheets-Sheet l I 1:: 5:11:41, to!

WILL/fill G. PRICE GEORGE E. FREDERICK INVENTORS ATTORNEY Filed March 30, 1961 United States Patent 3,117,675 KINEHC ENERGY ArbfiGRBlNG DEVECE Viilliam G. Price and George E. Frederick, South Bend,

ind, assipors, by mesne assignments, to ACF Industries, incorporated, New York, N.Y., a corporation of New .lersey Filed Mar. 3% 1961, Ser. No. 99,409 '7 flaims. ((31. 21343) The present invention relates to a kinetic energy absorbing device for the draft gear portion of rail-way equipment.

During the operation of coupling and hauling railroad cars substantial forces are communicated between the cars through their respective coupling gears. in order to reduce likelihood of damage both to the car and its freight, some provision must be made for cushioning these impact forces through the draft gears. One such cans is disclosed in application Serial No. 37,216, filed June 20, 1960, now Patent No. 2,994,442. In this patent, it is proposed that the cushioning take place by dissipating the kinetic energy frictionally and the balance of the cushioning takes place by a combination of air and hydraulic means. Thus the absorption or energy occurs through the three distinct media of friction, hydraulic fluid and resilient air spring means. The advantages of tris system are substantial, with the major advantage being that the frictional dissipating means are made more efiicient by developing a high initial resistance to telescoping movement of the cushioning device and thereby achieving a high normal load on the friction shoes at the very outset of cushioning movement so that the shoes dissipate a larger proportion of the couplin energy. The advantage of the hydraulic portion of the device is that it also develops a high initial resistance to telescoping movement which is maintained at a substantial value throughout the extent of the stroke so that the efhciency of the system is thereby improved.

it is an obiect of the present invention to retain all of the functional advantages of the system disclosed in the above-mentioned patent but to su'nplify construction of the device and also to reduce some of the servicing requirements of the system.

A further object of the invention is to provide a novel combination of frictional and hydraulic means which cooperate so that greater utility is obtained from the friction portion of the unit which dissipates a part of the energy frictionally in the form of heat and the balance of the absorbed energy is sustained by a hydraulic metering action in combination with resilient mechanical prings. The springs store sufficient energy to effect ension of the device when the coupling forces are relieved. it is intended that the described cushioning action take place during both bud and draft operations so that the jolting forces on the car become moderated before communicating with the car proper. Both the car and the contents are thereby safeguarded.

Other objects and features of the invention will become apparent from a detailed description of the device which proceeds with reference to the accompanying drawings wherein:

FIGURE 1 is a schematic view of the end of a railway car illustrating the location of the cushioning device, the car is shown in fragmentary view;

FIGURE 2 is art isometric view of the cushioning device as it is installed in the coupling structure;

FIG. 3 is a longitudinal section view of the cushioning device when it is fully extended, the upper half of the view being shown in longitudinal section and the lower half being wn in full line view with a portion of the Federated Jan. 14, 1964 casing broken away to illustrate the interior of the device; and

4 is the same view as FIGURE 3 but with the device compressed by the cushioning operation.

Referring now to FIGURE 1, there is shown a railway car lb which is part of a train of such cars, each car being connected to its adjacent car through a coupler 12 located at the end of the car. The car is supported on wheels 14- which are jounialled on an under-frame l6 ecured to the bed 18 of the car. All forces are communlcated to the car and from the car through the coupler 12;; such forces are referred to as draft forces when they are in the direction of the full line arrow or land forces when they are in the direction of the dashed line arrow (PZGURE 1).

Referring next to FIGURE 2, there is shown a center sill 26 which forms a part of the frame of the car and a horn 23 which limits the extent of stroking by the cushioning element during draft or buff operation. Both draft and buff forces are communicated to cushioning device 35 through a draw bar 32 having a fiat key 42 secured thereto, the key being movable within slot 44 of yoire 46. During bud operation the flat key 42 moves freely through the slot 44 but the end of the draw bar 32 being in engagement with follower plate 48 com resses the cushioning device 39 against flanges 56' forming a stop on the center sfll 26.

During draft operation, the draw bar 32 pulls the key 42 in the direction of the full line arrow (FIGURE 2) and the key being normally bottomed within slot 44 pulls the yoke 46 also in the direction of the full line arrov The follower plate 48 cannot move in the direction of the full line arrow farther than its position shown in FIGURE 2 because it engages a stop (not shown) provided by the center sill 2.6. Force from the drawbar 32 is thus communicated through the key 42 to the yoke 46 which then acts against the base 52 of the cushioning device 3tl which bears against the fixed follower plate 48 in the manner described. Thus, during both draft and buff operation all coupling forces are communicated to the center sill 26 of the car only after first having acted through the cushioning device 34? which moderates abrupt forces on the car.

Referring next to details of the cushioning device 33 (FIGURES 3 and 4) there is shown a casing 54, having at its open end 56 a number of friction surfaces 58 which taper inwardly from the open end of the casing; slidably mounted on these friction surfaces 58 is a number of shoes of which are spaced at regular circumferential intervals around the open end as. The construction of the device is thus far conventional, and for an illustration of one suitable cushioning device with which the present invention is usable, reference is made to the Miner draft gear class RF-N which was designed for a thirty-six inch pocket and previously included a number of rubber plates providing the necessary resilience to effect cushioning and extension of the device.

Between the follower plate 48 and shoes as is a wedge 62 having tapered surfaces 6-;- which are complementary with tapered surfaces 66 of the shoes 60. Relative sliding occurs both between surfaces 64 and 66 and between surface 58 of the casing and shoes 69. This sliding movement frictionally dissipates a part of the energy involved during draft and buff force occurrence. Frio tionally dissipated energy is in the form of heat which is carried off to the surroundings.

The shoes 6%? are in engagement with a backing plate 63 the center of which is inset to extend Within the open end of the casing. The outer flange 7% of the backing plate includes a number of bosses '72 which are received, one within an end of each coil spring 74 compressed between backing plate and base plate 76 which bears against cover plate '78 closing the end of the casing. Within the casln are two tubular members, one, secured to the bottom plate W5 by Welding as shown at 82 and the second tubular member 34-, secured to and movable by the backing plate The tubular member 34 has a piston 256 secured by pins the tubular memher and includes a metering orifice 9% contro led by meterinr "in 92. The outer ner ll er of the iston 85 e r P is sealed by some suitable sealn g ring 93 which is in slidable bearing with inner surlace of member 3%. During the com ression stroke of the device 3%), fluid is exhausted from chamber through orifice 9b and into chamber as where it exits through openmg 98 into an annular chamber ltltl, one wall which is delined by a com ressible 1%2 comprising spongc rubber or the e encased in a fluid impervious membrane of neoprene or other material nonreactive with hydraulic fluid. Fluid is prevented from leaking past the sponge rubber material 1&2 by means of an G-ring seal received wit in a groove of sealing ring ms. The sealing is clamped to the tubular member 3*? and is in slidable se ing engagement with tubular member 3dthrough a packing i 38 and an O-ring seal lltl.

As mentioned pre 'ously, during either draft or bull operations, the cu binning devi e wn be compressed so that it assumes the position shown in 'lG'LlRE 4 when subjected to external load. It is characteristic of fluid metering devices to off r nitial resistance to relative movement. Thus, she i there occur a sudden, lgh order of external load imposed on the draft gear this will tend to exhaust iluid very rapidly from chamber through the metering orifice 19 and into chamber 96 and a corresponding high order of resistance develops from the hydraulic medium which is communicated to the shoes 69 hrough piston 86 tubular member Since the shoes are unable to move except by displacing fluid from chamber 94, they tend to be rigidly held and develop a high order of resistance to translation by the follower plate 48. Therefore, as the wedge s2 tends to push the shoes 69 along surface 58, there also develops a high order of normal load bet een shoes 6% and surfaces 58 thereby increasing the amount of frictional dissipation of energy at the very outset of the coupling oieration. It should be noted, that relative sliding movement occurs not only between the shoes as and the casing but also between the shoes on and the wedge 62-. While there is considerable variation from one operation to the next in the proportion of energy which is abstracted frictionally, it has been substantiated, from numerous laboratory tests that frictional energy dis nation is realized in amounts far greater than obtained v *1 previous energy absorbing devices. The energy is f"- er absorbed by the hydraulic fluid medium, which in the process of being exhausted from chamber 94 under pressure into chambers and 1%, becomes heated and eventually communicates this heat to its surrounding structure. The tn. sorbing medium consists of the springs 74 which store energy as they are compressed from the position shown in FIGURE 3 to that of FIGURE 4. energy in Lhe'springs is then available for exteno g the device when external forces are relieved, thereby exhausting fluid from chamber lllil and returning the fluid through open- This ings to chamber 96 thence to chamber g4 "'arough metering orifice Duringext asion of the device, the

to i l h L l n movement 01 toe shoes so and 4 the normal load of the shoes 66 against their opposing surfaces. The spring force, however, in contrast to the hydraulic force, does not develop a high initial resistance and therefore if hydraulic means were elimin ted, high normal load for the shoes would not occur until the device were half or three-quarters compressed so that much less frictional dissipation could be realized. For maximum utilization of the iriction means it is necessary to develop the high initial resistance to shoe movement, this being a function of the hydraulic means and the more gradual buildup of resistance which is prov ed by .s of the device to their original position when external forces are relieved.

ZGURE 3 w erein cover plate 73 is in ement v 'rn stop 59 of the center and follower is in contact with its stop on ,ne center sill 2d. of the spring 74 ing device will be l'ully extended foiiowing each coup g operation.

Although the present invention has been descr bed in connection with but a single example ernbodime it will be understood that this is only illustrative of the invention and is in no sense restrictive thereof.

It is intended therefore that such revisions and variations as may be expected on the part of those skilled in the art to meet individual design preferences, will be included Wit in the scope of the fol owing claims as equivalents of the invention.

What is claimed is:

1. A kinetic energy absorb ng device for cushioning the impact of draft and bull" forces during coupling operations, said device comprising a casing providing frictional surfaces at one end thereof, a plurality of friction shoes disposed for slidable movement on said surfaces, wedge means acting against said shoes for spreading taem against said frictional surfaces and e fecting their slidable movement on said surfaces, a backing member proportioned to tit within said casing for reciprocal movement therein and in engagement with said shoes to oppose their movement, mechanical spring means disposed within said casing and compressed therein to urge said backing member to a normal at rest position extending said device and also opposing movement of said shoes farther within said casing, two variable volume hydraulic chambers within said casing including a metering orifice interconnecting said chambers whereby fluid is exhausted fro n one chamher through said orifice and into the other'chamber during contraction of said device accompanying either draft or bull operation, means for communicating hydraulic resistance from metering action to said backing member whereby high initial resistance is ollered to shoe movement at the onset of draft and buff operation, said hydraulic resistance being supplementary to said spring force, and compressible means within the one of said variable volume chambers which receives fluid during contraction of said device and reducible to accommodate the inflow of fluid therein.

2. A kinetic energy absorbing device for cushioning the impact of draft and bull forces comprising a casing providing frictional surfaces at the interior surface thereof, a plurality of friction shoes disposed for slidable movement on said friction surfaces, Wedge means engaging said shoes to effect spreading thereof against said friction surfaces and concurrent translatory movement on said friction surfaces, a backing member proportioned to fit within said casing for reciprocal movement therein, mechanical spring means compressed within said and bearing against said backing member to oppose movement of said shoes in one direction, and hydraulic means also for opposing shoe movement and complementary with s d springs in resisting shoe movement in a contracting direction, said hydraulic means including a rust tubular member, 21 second tubular member having a piston mounted for reciprocal movement within said first tubular member and operatively secured at the opposite end to said backing member, said tubular members defining therebetween two variable volume chambers, a metering orifice connecting said chambers, and a metering pin movable through Said orifice to control its effective area, and compressible means disposed within the one of said variable volume chambers which receive fluid therein and of reducible volume to accommodate the infiow of fluid therein.

3. A device for absorbing the kinetic energy impact of draft and buff o erations in railroad eq ipment comprising a draw bar having a coupling member at one end thereof and a slot in the other end thereof; a yoke assembly provided with a slot therein; an elongated means carried by said first named slot and extending into sliding engagement with said second named slot; a casing carried by said yoke assembly and movable therewithin, said casing being provided with friction surfaces at one end thereof; a wedge having inclined surfaces and being longitudinally movable; means providing an operable connection of said wedge with said draw bar for efiecting said movement on either draft or buff operations; longitudinally movable friction shoes located for engagement with said friction surfaces and slidably movable therealong as a result of wedge movement in the same direction; a first tubular member defining a first chamber; means forming an operative thrust connection between said shoes and said first tubular member to effect its telescoping movement within said casing, a second tubular member closed at both ends and affixed to said casing at one end; a piston connected to said first tubular member for reciprocal motion in said second tubular member, said piston dividing said second tubular member into two variable volume chambers; resilient means encompassing one of said chambers, said resilient means being responsive to the fiow of fluid within said chamber; a metering orifice in said piston communicating said first chamber with one of said variable volume chambers whereby fiuid is metered in its flow between said one variable volume chamber and said first chamber to dissipate impact energy and thereby aid said frictional means; a metering pin fixedly secured to said one end of said second tubular member controlling the effective area of said metering orifice; and spring means disposed within said casing and bearing at one end against said casing and at the other end being operatively connected with said shoes and said first tubular member to efiect extension of said device from its contracted position when draft or buff forces are relieved whereupon said resilient means aids in the substantial return of the fiuid from the recipient chamber to the fluid chamber where it is stored for further operations.

4. A railway draft gear for coupling cars and cushioning the impact of draft and bufi forces comprising a casing providing frictional surfaces at one end thereof; a plurality of shoes operatively connected to said frictional surfaces for translatory movement hereon; a movable Wedge operatively engaging said shoes to effect biasing effort thereon, said casing and said wedge both urging said shoes against their associated frictional surfaces and effecting translatory shoe movement on said surfaces; 21 member Within said casing engageable with said shoes;

6 at least one spring compressed within said casing and acting against said member to oppose translatory shoe movement in one direction; two variable volume hydraulic chambers; a compressible cellular material Within one variable volume chamber which chamber receives pressurized fluid as a result of the draft or buff operation to thereby effect deformation of said cellular material; a metering orifice corrnnunicating said chambers; means for controlling the effective area of said orifice; and means operatively connected to said member and responsive to the pressure drop across said metering orifice for communicating the hydraulic resistance to metering flow to said member for supplementing the resistance to wedge movement.

5. A device for absorbing the kinetic energy impact of draft and buff operations in railroad equipment comprising in combination a draw bar; a coupling member at one end of said draw bar; a casing; friction surfaces at one end of said casing; a wedge having inclined surfaces and being longitudinally movable by said draw bar; longitudinally movable friction shoes located for engagement with said friction surfaces and slidably movable thereon by said draw bar during draft or buff operation to frictionally absorb a part of the kinetic energy; a first tubular member; means forming an operative thrust connection between said shoes and said first tubular member to telescope said first tubular member Within said casing; a second tubular member defining a hydraulic cylinder within said casing; an end closure means for said second tubular member adapted to permit said first tubular means to slide therethrough; a sealing means to permit such translation of said first tubular member without loss of fluid; a piston associated with said first tubular means dividing said hydraulic cylinder into two variable volume chambers; means in said piston for permitting flow of fluid from one of said chambers to the other in a restricted manner and through said first tubular member; means associated with the fired end Wall of said cylinder for entry into the means in the piston permitting flow from one chamber to the other to further restrict said flow between chambers; an incased resilient means surrounding said first tubular member within said variable volume chamber that receives the fluid upon the occurrence of draft or buff forces to aid in returning said liquid upon extension of said device such as occurs upon relief of said forces; and coil spring means disposed Within said casing and bearing at one end against said casing and at the other end operatively against said shoes to effect extension of said device from its contracted position when draft or buff forces are relieved.

6. A device as claimed in claim 5 wherein said resilient means is a sponge rubber member surrounding said first tubular member.

7. A device as claimed in claim 5 wherein said resilient means is incased by an impervious neoprene membrane.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A KINETIC ENERGY ABSORBING DEVICE FOR CUSHIONING THE IMPACT OF DRAFT AND BUFF FORCES DURING COUPLING OPERATIONS, SAID DEVICE COMPRISING A CASING PROVIDING FRICTIONAL SURFACES AT ONE END THEREOF, A PLURALITY OF FRICTION SHOES DISPOSED FOR SLIDABLE MOVEMENT ON SAID SURFACES, WEDGE MEANS ACTING AGAINST SAID SHOES FOR SPREADING THEM AGAINST SAID FRICTIONAL SURFACES AND EFFECTING THEIR SLIDABLE MOVEMENT ON SAID SURFACES, A BACKING MEMBER PROPORTIONED TO FIT WITHIN SAID CASING FOR RECIPROCAL MOVEMENT THEREIN AND IN ENGAGEMENT WITH SAID SHOES TO OPPOSE THEIR MOVEMENT, MECHANICAL SPRING MEANS DISPOSED WITHIN SAID CASING AND COMPRESSED THEREIN TO URGE SAID BACKING MEMBER TO A NORMAL AT REST POSITION EXTENDING SAID DEVICE AND ALSO OPPOSING MOVEMENT OF SAID SHOES FARTHER WITHIN SAID CASING, TWO VARIABLE VOLUME HYDRAULIC CHAMBERS WITHIN SAID CASING INCLUDING A METERING ORIFICE INTERCONNECTING SAID CHAMBERS WHEREBY FLUID IS EXHAUSTED FROM ONE CHAMBER THROUGH SAID ORIFICE AND INTO THE OTHER CHAMBER DURING CONTRACTION OF SAID DEVICE ACCOMPANYING EITHER DRAFT OR BUFF OPERATION, MEANS FOR COMMUNICATING HYDRAULIC RESISTANCE FROM METERING ACTION TO SAID BACKING MEMBER WHEREBY HIGH INITIAL RESISTANCE IS OFFERED TO SHOE MOVEMENT AT THE ONSET OF DRAFT AND BUFF OPERATION, SAID HYDRAULIC RESISTANCE BEING SUPPLEMENTARY TO SAID SPRING FORCE, AND COMPRESSIBLE MEANS WITHIN THE ONE OF SAID VARIABLE VOLUME CHAMBERS WHICH RECEIVES FLUID DURING CONTRACTION OF SAID DEVICE AND REDUCIBLE TO ACCOMMODATE THE INFLOW OF FLUID THEREIN. 